Multimedia messaging service (MMS) is a standard for telephone messaging systems that allows sending messages that include multimedia objects (such as images, audio, video, rich text, etc.). An MMS-enabled mobile device may be used by a subscriber to compose and send and receive messages that include multimedia objects.
Second generation (2G), third generation (3G), and fourth generation (4G) mobile phone standards represent a family of standards under the International Mobile Telecommunications program. Generally, 3G and forthcoming 4G networks are wide area cellular telephone networks which can support MMS applications. In contrast, 2G networks have lower data transmission capabilities (compared to 3G and 4G) that may not support the full capabilities of an MMS-enabled mobile device. Currently, 3G network coverage is not universally available, such that a roaming MMS-enabled mobile device may sometimes rely on a 2G network for service.